Improvement in head-blocks



E. H-sTBAR-Ns. HEAD BLOCK.

No. 8l,837.

Patented Sept. 1, 1868.

UNITED STATES' PATENT OFFICE.

E. II. srEAnN s,'or EEIE, PENNSYLVANIA.

IMPRovEM ENT IN HEADfBLocKs.-

Specntlcn forming part ot' Letters Patent No. 81,837, dated September 1, i868.

To all whom it may concern.-

Be it known that I, E. H. STEARNs', of Erie, in the county of Erie and State of Pennsyl- Vania, have invented a new and useful Improvement in Head-Blocks for Saw-Mills; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawings, forming` part of this specification, in wl1ich-- Figure 1 is a plan or top view of my invention. Fig. 2 is anend View of the same. Fig. 3 is a transverse vertical section of the same,

'taken in the line .fr .r Fie. l.

Similar letters of reference indicate like parts.

This inventionrclates to a new and improved head-block for saw-mills; and it consists, first, in an automatic means employed .for-throwing back the knees of the head-block after a log has been sawed, so that the knees will be-in proper position to have a succeeding log dogged to them. The object of this part of the invention to avoid the labor and time now expended in moving back by hand the knees every time alog is sawed or turned upon the blocks or knee-guides. l

The invention consists, second, in a novel stop mechanism for limiting the backward movement of the knees in accordance with the size or diameter of the logs to be sawed, the object ofthis feature of the invention being to obtain a stop mechanism which may be operated and adjusted with the greatest facility, in order te control or limit the backward movement of the knees.

The invention consists, third, in a means employed for avoiding jars and concussions at the termination of the backward movement of the knees; and, finally, in amcans by which the dogs, after being liberated from the reniranged, and operatedinthe usual or any proper manner. l

B IB represent the two knee-guides of the head-block, which guides are firmly bolted transversely on the carriage at a suitable distance apart.

C C are the knees connected to or cast with slides D D, which are fitted in the guides In such ajmanner that they may move freely back and forth thereon. The knees C C may be moved forward to set. the log to the saw by any of the known means. The plan I shall probably use will be one formerlypatented by me, consisting of pawls operated by eccentries a on a shaft, E, the pawls engaging with racks at the under sides of the slides D D, and the shaft E operated by a hand-lever, F.

G is a shaft, which has its bearings in the guides B and in lugs b b, attached to the car- Tiage A. This shaft has a. pulley/132, keyedon each end of it, and these pulleys have each a chain, I, attached, which are connected to the slides D D. (See Figs. 1 and 3.)

0n the shaft G there are two spiral springs, J J, which are connected at one end to the pulleys H H, the opposite ends being connected to the bearings or lugs b b. rIhese springs, when the knees C C are being moved forward or the log set to the saw, are wound up, owing to the turning of the shaft G, through the media of the chains and pulleys, and hence it will be seen that at any time, when the slides D D are liberated from the means which moved them and the knees forward to set the log to the saw, the spring .I .I will draw the slides and knees instantly back. In the present instance I employ two shafts, K K, with ,cams on their ends to throw the pawls ont of gear with the racks at the under side of the slides; but other means would of course be employed with a different mechanism for setti ng the knees and log to the saw.

I do not confine myself to the pulleys and chains for forming a connection between tlie slides and springs J, for a rackzand pinion may be used, and probably various other means which will answerequally as goed a purpose may suggest themselves to one skilled in the art. Neither do I confine myself to spiral springs J, for coil-springs may be used, and alsoother springs; but probably the spiral springs will be most generally used. By this one to the outer side of each i knees is limited at different distances by means of notched segment-bars L, which are pivoted kneeruide, as shown at c. raised and lowered to greater or less height by means of eccentric-dogs M at the ends of a shaft, N, operated by a hand-lever, O. When the dogs M are so adjusted as to admit of the bars L being fully down, the knees are allowed to be brought back their extreme distance, a stop or projection, I, on the knees coming in contact with the rear shoulder, d, 0f the seg-'5 bars L are raised' ment-bars L; but when the in a greater or less degree a more forward shoulder will serve to resist the backward movement of the knees. The more elevated the bars the less backward movement the knees will have; hence it will be seen that the back' ward movement of the knees may be regulated according to the size or diameter of the logs being saWed, and from the same position or standpoint that the setting-lever F of the shaft E is v'operated lent means may be used for the purpose.

The stops or projections ]?,I construct on the buffer principle in order to avoid jars and concussions. One portion of the stop is com.- prised of an ear, c, which projects laterally from the lower-part of each knee, and the other portion is comprised of aplate, f, which is secured to e by a screw-bolt, g, a piece of indiarubber, a spring, or any elastic substance, h, being interposed between e and f, and the bolt allowed to work or move freely in e. By this arrangement a good and efficient buffer-stop for the knees is obtained, one which will ef- .fectually obviate all jars and concussions, and

prevent unnecessary wear and tear.

Q Q are the dogs,which maybe constructed -in the usual or any proper manner. The inner ends of these dogs are hooked in a'swivel,

lt, fitted in sockets S on the upper surfaces of These segment-bars L L may be the slides D n. This feature of the swivel is' edge of the flange, and in so doing will assume v a position at right angles with the knee-guide and parallel with the sides of the log-carriage. (See more particularly Fig. 1.) This position of the dogs places them out of the Way of all the working parts of the head-blocks, so that knees cannot be obstructed in their backward movement, and said position of the dogs renders them capable of being grasped with lfacility 'in order to be fitted into the log again,

or into a succeeding log. The dogs therefore,

it will be seen, adjust themselves automatically to this desirable position, no attention onthe part of the Sawyer being required in order to effect that end.

Having thus described my invention, I claim' as new and desire to secure by Letters Patent-'.-A

1. In head-blocks for saw-mills,the employment of springs so applied4 that when* theknees are released from the setting mechanism the springs will automatically bring back the knees to the required position for the next I dovnot confine myself to the eccentric-dogs M for adjusting .the bars L, for other equiva-j advancing movement,

substantially as V"set forth.

2. The segment-bars L, constructed, ar

ranged, and applied inthe manner shown, or in an equivalent way, for the purpose of -limiting the backward'movement of the knees, as

set forth. 3. The elastic -stops I upon the knees of the head-blocks, in combination'with the segmentf bars L, substantially as described, for the purpose specified. y

4. The flanges T, for the purpose of carrying and adjusting the dogs when disengaged from .the log or remnant thereof, substantially as described.

The above specification of my invention signed by me this 16th day of July, 1868.

E. H. STEARNS. Witnesses:

FRANK BLocKLEY, ALEX. F. RoBnR'rs. 

